Percutaneous absorption of ibuprofen from different formulations. Comparative study with gel, hydrophilic ointment and emulsion cream

In a three-way cross-over study on 6 healthy adult volunteers, the percutaneous absorption of ibuprofen (CAS 15687-27-1) was studied with 3 topical formulations containing 5% w/w ibuprofen in a gel (Iprogel) or in a hydrophilic ointment or in an emulsion cream. By analysis of the plasma drug concentrations appearing after topical application, the relative drug bioavailability was calculated in terms of Cmax (maximum blood concentration of the drug), AUC (area under the curve of drug plasma concentrations at various time points) and Tmax (the time required for appearance of maximum drug concentration in the blood). The gel formulation showed the highest drug concentration in blood, reached in the shortest period, whereas that from the hydrophilic ointment showed the lowest drug concentration, reached at the slowest rate. The absorption from the reference product containing the drug as an o/w emulsion cream was less than with the gel formulation but higher than that found with the hydrophilic ointment.